Controller for pump system

ABSTRACT

A pump control system includes a pump operable via actuation of an actuator that moves an actuating element to cause the pump to generate an intake stroke and a discharge stroke to pump media along a pipe or conduit. A sensor is disposed at the actuator and is operable to sense the position of the actuating element during operation of the actuator and pump. A controller is operable to control the actuator. The controller, responsive to an output of the sensor, determines the current position of the actuating element and automatically controls the actuator to provide a selected performance of the pump.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the filing benefits of U.S. provisional application Ser. No. 62/288,542, filed Jan. 29, 2016, which is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to the field of pumps and more particularly to the field of diaphragm pumps that are actuated to pump liquid through a pipe.

BACKGROUND OF THE INVENTION

It is known to provide a diaphragm pump that is operable to pump liquid by movement of a diaphragm element to cause intake of fluid (such as liquid or semi-solid media or the like) into the pump and discharge of fluid from the pump. The movement of the diaphragm element is caused by a piston and cylinder arrangement, whereby vertical movement of the piston imparts vertical movement of a center region of the diaphragm element. The actuation of the piston/cylinder is set to provide a desired stroke rate or stroke distance.

SUMMARY OF THE INVENTION

The present invention provides a pump control system for a pump that generates alarms or alerts to inform a user of a required operational change and/or that automatically controls the operation of the piston/cylinder and pump so that the pump provides a desired flow rate and/or stroke length and/or pressure irrespective of changes in viscosity of the fluid (such as liquid or semi-solid media or the like) being pumped or restrictions or blockages occurring in the pipes. The pump and control system of the present invention uses a single sensor, such as an ultrasonic sensor or probe to sense the location of the piston and utilizes the sensor data (output by the sensor to the controller) to determine optimum operation of the pump to meet desired input parameters. The system and its controller directly measure and adjust the piston and diaphragm position to automatically control operation of the pump, with minimal to no operator input required.

These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a pump and control system in accordance with the present invention;

FIG. 2 is a side elevation and partial sectional view of the pump system of FIG. 1, showing the pump drawing the diaphragm upward during an intake stroke of the pump;

FIG. 3 is another side elevation and partial sectional view of the pump system, showing the pump pushing the diaphragm downward during a discharge stroke of the pump;

FIG. 4 is a side elevation and partial sectional view of a pump and sensor probe of the controller of the present invention, shown disposed or installed at the top of the cylinder and operable to sense the position of the piston rod during operation of the cylinder and pump;

FIG. 5 is a plan view of a controller of the control system of the present invention;

FIGS. 6-13 show various exemplary control screens of the controller of FIG. 5;

FIG. 14 is a plan view of another controller of the control system of the present invention; and

FIGS. 15-18 show various exemplary control screens of the controller of FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depicted therein, a pump system 10 includes a controller 12 for controlling operation of a pump 14 for pumping fluid along a fluid line or pipe or conduit (FIG. 1). As shown in FIGS. 2 and 3, the pump 14 comprises a diaphragm pump that includes a diaphragm that moves responsive to actuation of an actuator 16, such as a pressurized gas or fluid cylinder (such as, for example, a pneumatic or hydraulic cylinder). The controller 12 is responsive to a sensor 18 (such as an ultrasonic sensor or probe) that is disposed or installed at the cylinder and senses the position of an actuating element or piston rod of the actuator or pneumatic (or hydraulic) cylinder 16, and controls the actuation of the actuator or cylinder accordingly, as discussed below. The controller 12 thus automatically controls the pump (or pumps) and can adjust the rate and/or length of the stroke of the cylinder and pump to enhance or optimize pump performance and/or to adjust the pump operation responsive to changes in fluid viscosity or density or pressure or the like, as also discussed below. The controller also or otherwise generates an alert or alarm to inform or alert the user that a required adjustment of one or more pump settings is required to enhance or optimize pump performance and/or to adjust the pump operation responsive to changes in fluid viscosity or density or pressure or the like, as also discussed below.

The pump controller directly measures and adjusts the diaphragm position with positive feedback. The controller can be readily set up for an existing pump, such as by connecting the control lines of the controller to the lines of the cylinder and connecting the sensor or probe at the cylinder.

During operation, the controller cycle rate may be responsive to an output signal (such as a 4-20 ma signal or the like) from the sensor, and may provide full adjustable suction and discharge pressures to match the system pressures. The system may provide full emergency shutdown for maximum safety, and may provide local and remote start/stop to facilitate easy pump operations. Optionally, the controller and system may provide a diaphragm monitor to determine the status of the diaphragm and to determine if leaks occur at the diaphragm. Optionally, and desirably, the controller may provide touch screen control to enhance the user's ability to adjust operation of the controller and pump.

With the continuous measuring of the position of the piston of the cylinder or actuator, and thus the position of the pump diaphragm, the controller can be set to maintain full suction and discharge strokes even with varying system conditions. The system may not allow the diaphragm to stop at the bottom of the discharge stroke. Thus, the pump is always full and never over pressurized, thereby optimizing or maximizing pump performance and diaphragm life.

In the illustrated embodiment, the controller uses an ultrasonic probe or senor that can be disposed in (such as by being pushed into) a hole at the top of the cylinder and that may send an output signal to the controller. The controller processes the signal to measure or determine the piston and diaphragm position and rate or speed continuously. This allows the controller to change the speed and timing of the pump diaphragm in real time.

The controller of the present invention provides automatic control of the pump operation. When the pump solenoid valve is idle (not energized), supply (fluid or gas or air) pressure is on the bottom side of the pump air cylinder (with the diaphragm accordingly being in the up or intake position as shown in FIG. 2) and the pump controller measures the position using feedback from the ultrasonic probe regarding the position. The controller processes or determines the position of the diaphragm and shifts the solenoid valve, diverting supply air to the top of the diaphragm (FIG. 3) to drive the diaphragm down for the discharge stroke. At the bottom of the stroke the solenoid is immediately de-energized. When the solenoid valve is de-energized, the solenoid valve shifts back to its idle position, the air pressure on the diaphragm is exhausted to atmosphere, and the supply air pressure returns to the bottom side of the air cylinder piston to lift the diaphragm assembly for the upward or suction stroke.

The control of the present invention provides positive stroke feedback (or control). For example, if the suction or discharge pressure is too low, the controller may generate or display a visual or audible alert or alarm at the controller or to a remote location. The operator thus knows to adjust the pressure at the cylinder to maintain a full stroke. The controller may control a single pump (as shown in FIG. 1) or may control two or more (such as four) pumps in sequence.

With reference to FIGS. 5-13, an embodiment of a smart pump controller of the present invention is shown, with different touch screen displays and user inputs or function keys (e.g., F1-F5) to allow an operator to set the controller for the desired or appropriate operation and control of the cylinder and pump, depending on the particular application of the controller and pump system. For example, FIG. 6 shows a startup screen that lists optional screens to select.

The controller device or box comprises a small programmable logic controller (PLC), an operator interface, and an optional diaphragm moisture detector. The operator interface enables the setting of pump operating parameters, as well as the monitoring, documenting, and resetting of pump alarms. The total run time and stroke count can also be monitored and reset through the operator interface. Through the operator interface, the stroke rate can be monitored and changed by an operator or user of the controller. Optionally, and desirably, if the controller detects moisture in the dry (upper) side of the diaphragm (such as responsive to a moisture sensor or the like disposed at the dry side of the diaphragm), the pump may be shut down and the controller may generate a diaphragm failure alarm or alert (such as an audible and/or visual alert).

As shown in FIG. 7, a first screen may allow the user to turn the pump on or off, while also displaying the current or actual pump rate, and optionally displaying remote operation of the pump and/or if the pump is operating in the short stroke mode. Another screen or input (FIG. 8) may allow the user to change the targeted or desired pump rate (strokes per minute). Other control screens or inputs may be provided to display various information, such as total cycles and maintenance cycles (FIG. 9), short stroke alarm or control and/or max stroke rate set point (FIG. 10), remote operation control (FIG. 11), calibration settings and setting the position of the piston at the top of the stroke (FIG. 12) and at the bottom of the stroke (FIG. 13) and the like.

The controller of the present invention is designed to maximize the pump system's efficiency with minimal operator input. The controller can automatically adjust the discharge and suction pressure independently to achieve the desired stroke rate for the current system conditions. The pumping system will use only the amount of air required to achieve the current desired stroke rate.

As discussed above, the controller uses the ultrasonic probe to actively monitor the position of the diaphragm of the pump or pumps. This information is continuously used by the controller to make adjustments to the pump's discharge and suction timers and pressures. The user input touchscreen is designed to simplify controller setup and pump system monitoring. By using an Ethernet port or connection, the controller may be remotely accessed and operated from a laptop, desktop, or smart phone. The controller is responsive to the signal from the sensor or probe to set stroke rate, and may also be responsive to a remote start/stop Input. If the controller has a moisture detection option, connections for an external moisture alarm switch may be provided.

Thus, the controller of the present invention is a device used for all pump control and monitoring, as well as alarm response. As shown in FIG. 1, all inputs and outputs are connected to the controller. The programming is designed to automatically adjust the pump stroke rate to achieve the operator's desired stroke rate that is selected for the particular system and desired flow of the fluid or media in the pipe or conduit. If the discharge or suction regulated air pressure needs to be adjusted, the controller may adjust the air pressure or may display a message on the operator screen, so that the operator can adjust the air pressure, until the desired air pressure is reached. The pressures need to be set to the required pressure to move the pump in its suction and discharge stroke. This assists the operator with setting the suction and discharge air regulators for the current pumping condition and not over consuming the air supply at the plant or facility.

Optionally, the control may provide automatic control of the pump (more than generating an alert). For example, a smart pump control of the present invention can replace system pressure transmitters, flow meters, density meters and/or other process feedback instruments. The control thus may be an integral part of the complete process control system. The alarm and display functions may be transmitted remotely to a central control via a wired link or a wireless communication connection. An example being the touch screen display for such a controller (FIG. 14), with example screens/inputs shown in FIGS. 15-18. For example, FIG. 15 shows a calibration input screen to provide for calibration of the probe or sensor and/or the air regulators of the pump/system, while FIG. 16 shows an input screen that allows a user to select the desired function of the controller, such as to maintain a desired stroke rate and/or maximum pressure or the like, and FIG. 17 shows an input screen for maintenance of the pump or system, and FIG. 18 shows an input or operation screen that shows the current function of the pump and system (so an operator can readily monitor the operation of the pump system to make sure the system is operating within the desired stroke rate and pressures).

The controller may automatically adjust the pressure if the system determines that the pump does not have enough air pressure or an excess of air pressure on either the suction or discharge stroke. Optionally, instead of automatically adjusting or increasing the pressure, the system may generate an alert or alarm to indicate to an operator that the pressure needs to be adjusted or increased. The controller thus functions to enhance or maximize flow and reduce or minimize air usage.

Optionally, when the short stroke control feature is activated, the pump can be used to feed a plate filter press, where the pump may stall and continue to tap the press with a pressure pulse to enhance or maximize flow and reduce or minimize air usage, as well as increase filter cake density. Optionally, the system may operate to hold a set system pressure at or near a constant level.

The controller thus allows the short stroke mode to be turned on or off. During operation, the pumps are always trying to take a full stroke to maximize efficiency. The operator can set the maximum discharge pressure that is desired. When the discharge pressure created by the pumps is no longer enough to move the media in a desired discharge time, the pump will short stroke or “pulse.”

The controller will control the pump(s) to short stroke while maintaining the desired suction and discharge times but not increasing the discharge pressure beyond the set maximum pressure. The controller and pump(s) will exit the short stroke mode and return to normal operation after they reach a predetermined number (such as 10 or 20) full strokes or if they are stopped and restarted. Optionally, if the pump(s) are stopped and restarted, the discharge pressure will be reduced (such as by about 30 percent) upon restart and then automatically adjusted by the controller for the discharge system conditions.

The controller of the present invention allows for and adapts the pump system to changes in the liquid or media being pumped and to changes in the system. For example, the control may be set to maintain a set stroke rate, such that the control will maintain the stroke rate even if the fluid viscosity, density and/or other liquid or media characteristics change. The control, responsive to the signal from the sensor or probe 18, will automatically increase or decrease the suction or discharge pressure as required by the pump and system to maintain the desired stroke rate or the like.

In situations where the pump controller controls two or more pumps in sequence (such as, for example, four pumps in sequence), the controller may control the pumps such that each pump will stroke out of phase with the other pumps, thereby reducing pressure pulsations.

Thus, the controller of the present invention makes the pump a true process system that can be used to pace a flow rate or follow a pressure. The controller can hold the level of a reactor or tank making the system an excellent reactor bottom pump. The controller can handle system upset conditions with varying conditions, and can automatically compensate for different products in the same process system.

The controller of the present invention is also suitable for use with suction lift pumps (where suction is applied to raise the diaphragm during an intake stroke) and adjusts the suction regulator to fully raise the diaphragm without slamming the piston on the top of the cylinder. This can be tailored to the viscosity and suction lift of the liquid being pumped and the system by varying the suction. The controller will maintain the correct internal pipe velocity to enhance or maximize performance, while minimizing the air usage and increasing the efficiency of the pump system.

Therefore, the controller and pump system of the present invention provides a complete pump system that is tailored to the particular application and desired pump outputs. The pump is easily controlled over 0 to maximum flow of the pump. The controller's operating parameters can be quickly modified or automatically adjusted for upset conditions. The controller thus provides simple and easy pressure and flow control.

The controller of the present invention thus continuously measures the position and speed of the diaphragm on the suction and discharge stroke, and gives direct feedback to the user of the position. The controller uses the position/speed information to calculate or determine the optimum operating suction and discharge pressures for the pump, ensure that the pump always takes a complete stroke, ensure that the diaphragm is never in an unbalanced state during the discharge stroke, minimize the air flow rate (SCFM) used by the pump, maximize the efficiency and reliability of the pump. The controller automatically corrects for system changes (such as changes in pressures, viscosity of the pumped media, and/or density of the pumped media) without requiring additional instrumentation (such as density meters or viscometers) or process inputs. The controller does this without requiring user input, other than initial set up of the controller, such that the controller automates the pump and provides enhanced performance and enhanced efficiency of the pump or pumps.

Changes and modifications in the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law. 

1. A pump control system comprising: a pump operable via actuation of an actuator that moves an actuating element to cause the pump to generate an intake stroke and a discharge stroke to pump media along a pipe or conduit; a sensor disposed at the actuator and operable to sense the position of the actuating element during operation of the actuator and pump; and a controller operable to control the actuator, wherein the controller, responsive to an output of the sensor, determines the current position of the actuating element and automatically controls the actuator to provide a selected performance of the pump.
 2. The pump control system of claim 1, wherein the selected performance comprises a selected stroke rate of the pump.
 3. The pump control system of claim 1, wherein the selected performance comprises a selected pump discharge pressure.
 4. The pump control system of claim 1, wherein the actuator comprises a pneumatic or hydraulic cylinder and the actuating element comprises a piston that moves within the cylinder responsive to pressurization of the cylinder.
 5. The pump control system of claim 4, wherein the sensor comprises an ultrasonic sensor disposed at an end region of the cylinder to sense the location of the piston relative to the cylinder.
 6. The pump control system of claim 4, wherein the pump comprises a diaphragm pump and wherein the piston moves relative to the cylinder to move a diaphragm element of the diaphragm pump.
 7. The pump control system of claim 1, wherein the actuator comprises a suction device that applies suction at the pump to draw a diaphragm of the pump upward during an intake stroke of the pump.
 8. The pump control system of claim 1, wherein the controller is operable to control the actuator to provide the selected performance of the pump irrespective of changes in viscosity of the media pumped by the pump.
 9. The pump control system of claim 1, wherein the controller is operable to control the actuator to provide the selected performance of the pump irrespective of changes in pressure in the pipe or conduit.
 10. The pump control system of claim 1, wherein the controller is operable to control a stroke rate of the pump irrespective of changes in pressure in the pipe or conduit.
 11. The pump control system of claim 1, wherein the controller is operable to control a stroke rate of the pump irrespective of changes in viscosity of the media pumped by the pump.
 12. The pump control system of claim 1, wherein the controller adjusts operation of the pump responsive to changes in pressure in the pipe or conduit.
 13. The pump control system of claim 1, wherein the controller adjusts operation of the pump responsive to changes in viscosity of the media pumped by the pump.
 14. The pump control system of claim 1, wherein the controller is operable to control the actuator to enhance efficiency of the pump.
 15. The pump control system of claim 1, wherein the controller continuously determines the position of the actuating element during operation of the actuator and pump.
 16. The pump control system of claim 15, wherein the controller determines and applies optimum operating suction and discharge pressures of the pump.
 17. The pump control system of claim 15, wherein the controller controls the actuator to make the pump take a complete stroke during operation of the pump.
 18. The pump control system of claim 1, wherein, responsive to a determination of a partial blockage condition of the pipe or conduit, the controller switches the pump to a short stroke mode.
 19. The pump control system of claim 1, wherein the system comprises a plurality of pumps and a sensor disposed at an actuator of each of the pumps, and wherein the controller, responsive to the outputs of the sensors, automatically controls the actuators to provide selected performance of the pumps.
 20. The pump control system of claim 19, wherein the controller is operable to control the pumps such that each pump will stroke at least partially out of phase with the other pumps. 